from django.shortcuts import render, get_object_or_404
from django.http import HttpResponse, Http404, HttpResponseRedirect
from django.urls import reverse
from django.views import generic

from .models import Question, Choice


# Create your views here.


class IndexView(generic.ListView):
    template_name = 'polls/index.html'
    context_object_name = 'latest_question_list'

    def get_queryset(self):
        """返回最近发布的5个问卷."""
        return Question.objects.order_by('-pub_date')[:5]

# def index(request):
#     latest_question_list = Question.objects.order_by('-pub_date')[:5]
#     context = {'latest_question_list': latest_question_list}
#     return render(request, 'polls/index.html', context)

    # 硬编码
    # latest_question_list = Question.objects.order_by('-pub_date')[:5]
    # output = ', '.join([q.question_text for q in latest_question_list])
    # return HttpResponse(output)

    # return HttpResponse("Hello, World. You're at the polls index.")


class DetailView(generic.DetailView):
    model = Question
    template_name = 'polls/detail.html'

# def detail(request, question_id):
#     question = get_object_or_404(Question, pk=question_id)
#     return render(request, 'polls/detail.html', {'question': question})

    # try:
    #     question = Question.objects.get(pk=question_id)
    # except Question.DoesNotExist:
    #     raise Http404("Question does not exist")
    # return render(request, 'polls/detail.html', {'question': question})

    # return HttpResponse("You're looking at question %s." % question_id)


class ResultsView(generic.DetailView):
    model = Question
    template_name = 'polls/results.html'

# def results(request, question_id):
#     question = get_object_or_404(Question, pk=question_id)
#     return render(request, 'polls/results.html', {'question': question})

    # response = "You're looking at the results of question %s."
    # return HttpResponse(response % question_id)


def vote(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    try:
        selected_choice = question.choice_set.get(pk=request.POST['choice'])
    except (KeyError, Choice.DoesNotExist):
        # 发生choice未找到异常时，重新返回表单页面，并给出提示信息
        return render(request, 'polls/detail.html', {
            'question': question,
            'error_message': "You didn't select a choice.",
        })
    else:
        selected_choice.votes += 1
        selected_choice.save()
        # 成功处理数据后，自动跳转到结果页面，防止用户连续多次提交。
        return HttpResponseRedirect(reverse('polls:results', args=(question.id,)))
    # return HttpResponse("You're voting on question %s." % question_id)

